Professor Axel R. Preis, Charite-Universitatsmedizin, Berlin, Germany, speaks to Cardio Debate & Radcliffe Cardiology about coronary microcirculatory pathophysiology and if we can afford for it to remain a black box, during the ESC2016 Congress held in Rome, Italy.

Could you briefly describe why the coronary microcirculation plays an important role in CAD/myocardial ischaemia?
The microcirculation is actually the ‘business end’ of the circulation, because in the smallest vessels, which distribute all the materials, the oxygen and nutrition, and everything, you have a very small diffusion distance to the actual working myocyte. So you need a very working microcirculation to have a well-supplied myocyte array.

It’s a little bit like small roads in a town. You couldn’t supply a town only by big roads, you need the small roads to reach every single house.

And over the last 10, 20 years there’s more and more evidence that problems in microcirculation underlie a number of diseases that lead to myocardial problems.

Many people come into the hospital and you look at the large vessels, and the large vessels are okay. But still they have angina and have problems with the heart. And then the assumption is that the microvessels are disturbed and there is somehow a problem with the microvessels.

What research should be conducted to help us understand its role better and guide medical therapy?
That’s an interesting question. Over the last 30 years there has been a shift from mechanistical research in animals in addition to what we do in man, towards imaging research mostly in men. Which is good on one hand because we want to use as little animals as possible. But on the other hand we lose the capacity to find out what is really the mechanisms. And that can only really be done in the model when you can change things.

And therefore what I think is needed is something we want to call a Coronary Microvascular Observatory, where you can look into the microvessels of a beating heart and see what kinds of problems appear. Are they occluded? Are there leukocyte-endothelium interactions? Are they compressed by the tissue pressure? Are there inflammatory processes? And these days this can be done very well by modern microscopic techniques.

During the last 10 or 15 years the development of two-photon microscopy, of photo-acoustic microscopy, of light-sheet microscopy have all enlarged the array of possible investigation tools so much that we can now focus on these things.

But you need to bring together experts from the functional cardiac site or the vascular site, and these people who can deal with these modern microscopes.

It’s really like an astronomical observatory where you need one guy to fix the lense and deal with all the physics, and another one having to question, with respect to science.

And this should come together on a large scale, creating groups – with one group bringing the questions and another group saying how they can address these questions.